Just figured out a much better method to enable console in World of Goo. (Windows only)
Here's how.

1. Get a hex file editor. (e.g. WinHex)
2. Open WorldOfGoo.exe with your editor. (remember to backup!)
3. Go to offset 0x16c, change 0x02 to 0x03.
4. Save and run the game.

There were no code changes in 1.30 so it works for 1.20 and 1.30. Not sure for other versions.
Explanation: According to this article, 2 is for WINDOWS_GUI and 3 is for WINDOWS_CUI.